Messages

341

General Mach Discussion / Re: chip control on cnc lathe

« on: August 30, 2008, 12:07:35 PM »

You have my sympathy.

I set up my lathe, worked out feed and speed etc. and got some superb steel cuttings - as you say - about three feet long - in steel, and was congratulating myself on such a good set up, when the whole thing wrapped round the chuck, picked up some more swarf out of the tray and then proceeded to rip out the wiring to my limit switches.

I will adjust speed and feed 

342

General Mach Discussion / Re: Simple Zero VB script runs in VB but dose nothing in my G-Code...

« on: August 28, 2008, 05:08:10 AM »

Where did you save it - it needs to be in the Macros folder - then Mach 3 turn or Mach3 mill - whichever.

343

General Mach Discussion / Re: Auto Tool zero. Which Input etc. do I Use?

« on: August 26, 2008, 12:04:36 PM »

If you look on the list of Ports and Pins/Input Pins then whatever pin you allocate to "Probe" is the one.

I haven't used this feature (yet) but I assume that if it is then "earthed" then movement on the aixis will stop.
I would try it and see. What I have seen of this is that the pin is connected to the pad. The tool (which should be earthed)comes down and touches the pad and the axis stops.

I can't really say much more - I am sure someone who uses it will comment.

344

General Mach Discussion / Re: To many Nodes?

« on: August 24, 2008, 12:08:22 PM »

Yes - my apologies - I never thought of that

Bruce - I hope we have not gone too far off the subject.

345

General Mach Discussion / Re: Homing Probem

« on: August 24, 2008, 04:35:40 AM »

On the "settings" page make sure "auto limit overide" is flagged. This allows you to "back off" a limit switch.

Is the problem always with the same switch. If it is, the switch is probably "noisy" and giving multiple on/off signals as it opens - hence checking the "debounce" as Brett says. If it is not too much trouble you can replace the switch.

346

General Mach Discussion / Re: To many Nodes?

« on: August 24, 2008, 04:27:12 AM »

That may be, but Bruce was, I am sure, talking about "jerky movement" - which we have discussed many times.

A CAM program may arc aroung sharp corners ( I remain to be convinced) but I am sure that Bruces program, where it is describing an arc as many short straight lines, does not, and as we know, if you have exact stop, the machine will stop at each line.

I was asking Bruce if he was using "Exact Stop" or "Constant Velocity" and trying to explain the difference.

On the CAM program and sharp corners - how does the program know if my machine is in Exact Stop or Constant Velocity. If two lines of GCode follow one another, and describe two cuts at right angles to one another (or any other angle for that matter) Constant Velocity will round the corner. The way it works, it must do. I appreciate that by writing additional code you can go past the angle, and then return so that it does not round the corner. I have not delved enough into tool diameter compensation to comment on that, I am still taking lessons from Graham Waterworth

347

General Mach Discussion / Re: Offset tangential control?

« on: August 23, 2008, 04:14:50 AM »

Looking at it, it appears to be a circular saw held on two axis. I assume the saw position can be moved into or out from the central pivot, and the central pivot is a rotary axis.

Cutting outside the shape, as shown, the centre of rotation will be from the inside edge of the saw, to the central pivot, the width of the blade as it swings just cuts outside the line.

It would be difficult to calculate if you were cutting an inside edge though.

348

General Mach Discussion / Re: To many Nodes?

« on: August 23, 2008, 03:59:08 AM »

The majority of CAD CAM programs do NOT produce curves and arcs, but actually produce a vast number of short straight lines to produce the arc. You can see why, because looking at an arc, unless it was reqular shape to which there is a mathmatical formula (e.g. a circle, or elipse etc.) it would be impossible to mathematically predict where the curve would go next.

GCode requires a seperate line for each of these short straight lines.

If you have your machine on Exact Stop (Config/General Config - 2nd Column), then the machine does that - all axis stop after each line - which accurately produces the shape written. It does however produce what appears to be jerky movement - since some of the lines will only be millimetres, or fractions of an inch long.

If you downgrade the resolution, the CAM produces fewer lines, resulting in fewer stops, producing less jerky movement.

You can change your machine to Constant Velocity and here, Mach 3 calculates the next line, and, as it is slowing at the end of the prrevious line, it also accelerates into the next line, so the machine does not stop.

The disadvantage (or advantage of this) is that it also smooths out corners - i,e, the points disapear - so if describing an arc it can actually help to produce a smoother curve. Because the machine does not stop, it is less jerky.

If you are, however, in the same program also cutting sharp corners, you need to change back to exact stop to do so, since constant velocity rounds corners, whether cutting inside or outside the shape.

349

General Mach Discussion / Re: Configuration Issues

« on: August 21, 2008, 02:50:52 PM »

The Campbell breakout board is a *** to use. Have you got any manual with it. You cannot wire it up without a manual. You can download this.

If you look he has allocated the pins outs in an odd-ball way having the steps on pins 2,3,4,5 and the dirs on 6.7.8.9 - thats a new one on me.

You must allocated the Ports and pins as per Campbells system, otherwise it will not work. He has tried to be all things to all men.

You would be better to get an UNPOWERED break out board. Your Gecko drives are Opto isolated so they are safe enough. The only thing you would need is a 5 volt power supply to provide the 5 volt reference for the Gecko Opto isolation. Use a phone charger and a 5v regulator.

It would be a lot cheaper than Campbells board which is shown as $130 on the web site.

350

General Mach Discussion / Re: Mach 3 freezeing/simulation mode

« on: August 21, 2008, 02:33:06 PM »

I have Mach3 on my office computer, as well as the one in the workshop.

I have nothing attached to the office computer, but I do have Mach3 set up on it, as though it were running a machine, e.g. the ports and pins are allocated correctly, and all the bits I do not have are all correctly ticked as not being present e.g. none of the switches are activated. (I set it up the same as the workshop computer so I can write GCode programs on it)

I assume you have the drivers installed, and the machine told you it was installed correctly.

What you can do is run a driver test - the program is in the folder (or on your Desktop).

What may be happening is that you are running programs that are waiting for inputs from a switch or something else that you have shown active but do not have.

You might try the Smooth Stepper as a better alternative to a PCI card.
The Smooth Stepper simply plugs into a USB port and provides more inputs and outputs than the standard card. It also generates the pulses for the stepper motor/servo motor drivers - and therefore take a major task off your computer - allowing it to run more efficiently.